COURSE: GEOMORPHOLOGY-ORIGIN AND EVOLUTION OF EARTH AND RELATED THEORIES LESSON: VOLCANOES PRESENTED BY BHUMIKA SAINI
About me .B Tech from MNIT, Jaipur Interests: Reading, Playing Badminton Appeared in CSE interview thrice Three years of experience in teaching .Course fee: CONTRIBUTE Follow me on Unacademy: https://unacademy.in/user/BhumikaSaini me on Unacademy: httpsi//unacademyin/user/BhumikaSaini
Volcanoes A volcano is a rupture on the crust of Earth that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface . Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods.
PARTS OF VOLCANOE Crater Lava Side Vent Main Vent
Plate tectonics and volcanoes . Plate tectonics provides the most logical explanation of volcanoes and earthquakes There are 3 types of plate boundaries along which earthquake occurs 1.Convergent . 2 Divergent 3 Transform
The Continental Plates Plate Americali Pacific Plate African Fiat Nazca, Sout american Plate IndianAustralian Plate Antarctic Plate I spreading boundary converging boundary /Transform boundary
VOLCANOES INTERPLATE INTRAPLATE CONVERGENT BOUNDARY DIVERGENT HOTSPOT BOUNDARY
Three Basic Types of Plate Boundaries SCHEMATIC CROSS SECTION OF PLATE TECTONICS CONVERGENT PLATE BOUNDARY CONTINENTAL RIFT ZONE YOUNG DIVERGENT PLATE BOUNDARY DIVERGENT CONVERGENT PLATE BOUNDARY TRANSFORM PLATE BOUNDARY PLATE BOUNDARY SHIELD VOLCANO STRATO- HOSPHERE CONTINENTAL CRUST OGEANIC CRUSTSUBDUCT NMANTE OCEANIC CRUST Moho HOTSPOT ASTHENOSPHERE MANTLE
VOLCANO FORMATION: HOT SPOTS Direction of Plate Hot Spot A fixed source of magma North rising beneath a plate forming volcanic islan Eurasiarn Amorican co o Plate Plate Plate Pacific African Plate Nazca South Nazca-Amon n . Magma can be basaltic or Plate Australa AustraiaAindian gra itic -so eruptions can be explosive or "quiet te at plate Antarctica Plate HOT SPOT BOUNDARY BETWEEN TECTONIC PLATE ATE ONIC PL
Global Distribution of Volcanoes . Along divergent plate boundaries, such as Oceanic Ridges . Along converging plate boundaries where subduction is occurring. And, in areas called "hot spots" that are usually located in the interior of plates, away from the plate margins.
World Map of Volcanoes
Composite Cones . Composite Cone volcanoes are steep-sided made of alternate layers of ash and lava. Often the lava cools to create a plug in the vent, meaning that a huge explosion is needed to remove it. The best example is Mt. St. Helens. Subsiduary Cone Volcano made of alternating layers of ash and lava Steep sided
Geysers, Fumaroles and Hot Springs .A fumarole is vent where gases, either from a magm a body at depth or steam from heated groundwater, emerges at the surface of the Earth Hot springs or thermal springs are areas where hot water comes to the surface of the Earth. .Cool groundwater moves downward and is heated by a body of magma or hot rock. . Minerals dissolved in the high temperature water are often precipitated when the water cools at the surface.
INTRUSIVE AND EXTRUSIVE LANDFORMS Volcanic cones Craters, caldera Lava domes, plains Extrusive Batholith Laccolith Phacolith Lopolith Sill, dykes Volcanic plugs Intrusive
Intrusive landforms Intrusion of Magma in sedimentary rocks Sills (Horizontal) Dyke (Vertical) Laccolith - magma which could not come out Lopolith - saucer-shaped Phacolith - shape like waves Batholith - intrusive granitic rock e Lopolith - saucer-shaped
Volcano Lava flows & Pyroclastic deposits Volcanic neck Dike Sill Sill Laccolith Stock Dike Dike Batholith
B Tech from MNIT, Jaipur. Appeared in CSE interview thrice. Loves teaching and playing badminton.